Low voltage power system for a transport refrigeration unit

ABSTRACT

A low-voltage system of a transport refrigeration unit (TRU) includes a low-voltage direct current (LVDC) source; and a distribution bus coupled to the LVDC, the distribution bus is coupled to a compressor, at least one condenser, and at least one evaporator.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 63/296,343 filed Jan. 4, 2022, all of which are incorporated herein by reference in their entirety.

BACKGROUND

The present disclosure relates to transport refrigeration units, and more specifically, to low voltage power systems for a transport refrigeration unit (TRU).

Transport refrigeration units are used to cool cargo in a trailer or cargo container. Existing transport refrigeration units employ an engine and a generator to produce electrical power (e.g., AC power) to drive the compressor and fans (e.g., evaporator fans, condenser fans). Existing sources of AC power produce unregulated AC power that can vary in voltage and frequency. There may be a need for an all-electric solution for providing AC and DC power to the various loads for transport refrigeration units.

BRIEF DESCRIPTION

According to an embodiment, a low-voltage system of a transport refrigeration unit (TRU) is provided. The system can include a low-voltage direct current (LVDC) source; and a distribution bus coupled to the LVDC, wherein the distribution bus is coupled to a compressor, at least one condenser, and at least one evaporator.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a distribution bus that is a low voltage DC distribution bus.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a distribution bus that is coupled to a compressor bus, an evaporator bus, and a condenser bus.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises a DC motor that is mechanically coupled to an open drive compressor, wherein the evaporator bus and the condenser bus are coupled to at least one DC-DC buck converter that is used to convert voltage from the distribution bus for the at least one evaporator and the at least one condenser.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises a DC motor that is mechanically coupled to an open drive compressor, wherein the evaporator bus comprises at least one first DC-DC buck converter to convert voltage from the distribution bus for the at least one evaporator, wherein the condenser bus comprises at least one second DC-DC buck converter to convert voltage from the distribution bus for the at least one condenser, wherein the at least one first DC-DC buck converter and the at least one second DC-DC converter are different DC-DC converters.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises a DC motor that is mechanically coupled to an open drive compressor, wherein the evaporator bus comprises a DC-DC boost converter coupled to the at least one DC-AC converter, wherein the condenser bus comprises a DC/DC boost converter coupled to the at least one DC-AC converter.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus comprises a DC/DC boost converter coupled to a DC/AC converter, wherein the evaporator bus and the condenser bus are coupled to at least one DC-DC buck converter that is used to convert voltage from the distribution bus for the at least one evaporator and the at least one condenser.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises a DC-DC boost converter coupled to a DC/AC converter, wherein the evaporator bus comprises at least one first DC-DC buck converter coupled to the at least one evaporator, wherein the condenser bus comprises at least one second DC-DC buck converter coupled to the at least one condenser, wherein the at least one first DC-DC buck converter and the at least one second DC-DC converter are different DC-DC converters.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises a DC-DC boost converter that is coupled to a DC-AC converter, wherein the evaporator bus comprises a DC-DC boost converter that is coupled to a DC-AC converter that is further coupled to the at least one evaporator, wherein the condenser bus comprises a DC-DC boost converter that is coupled to a DC-AC converter that is further coupled to the at least one condenser.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a first converter coupling the LVDC source to the distribution bus, wherein the distribution bus is a high-voltage DC distribution bus that is further coupled to a compressor bus coupled to the compressor, an evaporator bus coupled to the at least one evaporator, and a condenser bus coupled to the at least one condenser, wherein the first converter is a DC-DC boost converter configured to increase a voltage from the LVDC source.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises a DC motor and a DC-DC buck converter configured to convert voltage from the distribution bus, wherein the DC motor is mechanically coupled to an open drive compressor, wherein the evaporator bus and the condenser bus are coupled to at least one DC-DC buck converter that is used to convert voltage from the distribution bus for the at least one evaporator and the at least one condenser.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises a DC motor and a DC-DC buck converter configured to convert voltage from the distribution bus, wherein the DC motor is mechanically coupled to an open drive compressor, wherein the evaporator bus comprises at least one first DC-DC buck converter coupled to the at least one evaporator, wherein the condenser bus comprises at least one second DC-DC buck converter coupled to the at least one condenser, wherein the at least one first DC-DC buck converter and the at least one second DC-DC converter are different DC-DC converters.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises a DC motor and a DC-DC buck converter to convert voltage from the distribution bus, wherein the DC motor is mechanically coupled to an open drive compressor, wherein the evaporator bus comprises at least one DC-AC converter coupled to the at least one evaporator, wherein the condenser bus comprises at least one DC-AC converter coupled to the at least one condenser.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises a DC-AC converter coupled to a motor, wherein the evaporator bus and the condenser bus are coupled to at least one DC-DC buck converter that is used to convert voltage from the distribution bus for the at least one evaporator and the at least one condenser.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises a DC-AC converter coupled to a motor, wherein the evaporator bus comprises at least one first DC-DC buck converter coupled to the at least one evaporator, wherein the condenser bus comprises at least one second DC-DC buck converter coupled to the at least one condenser, wherein the at least one first DC-DC buck converter and the at least one second DC-DC buck converter are different DC-DC buck converters.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises a DC-AC converter coupled to a motor, wherein the evaporator bus comprises at least one first DC-AC converter coupled to the at least one evaporator, wherein the condenser bus comprises at least one second DC-AC converter coupled to the at least one condenser, wherein the at least one first DC-AC converter and the at least one second DC-AC converter are different DC-AC converters.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a first converter coupling the LVDC source to the distribution bus, wherein the distribution bus is a high-voltage AC distribution bus, wherein the distribution bus is coupled to the compressor bus, the evaporator bus, and the condenser bus.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises an AC-DC converter coupled to a DC-DC buck converter that is further coupled to the DC motor, wherein the DC motor is further mechanically coupled to an open drive compressor, wherein the evaporator bus and the condenser bus comprise an AC-DC converter coupled to at least one DC-DC buck converter, wherein the at least one DC-DC buck converter that is used to convert voltage from the distribution bus for the at least one evaporator and the at least one condenser.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises an AC-DC converter coupled to a DC-DC buck converter that is further coupled to the DC motor, wherein the DC motor is further mechanically coupled to an open drive compressor, wherein the evaporator bus comprises an AC-DC converter coupled to a DC-DC buck converter that is further coupled to the at least one evaporator, wherein the condenser bus comprises an AC-DC converter coupled to a DC-DC buck converter that is further coupled to the at least one condenser.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises an AC-DC converter coupled to a DC-DC buck converter coupled to the DC motor, wherein the DC motor is further mechanically coupled to an open drive compressor, wherein the evaporator bus comprises an AC-DC converter coupled to a DC-AC converter, wherein the condenser bus comprises an AC-DC converter coupled to an DC-AC converter.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises an AC-DC converter coupled to a DC-AC converter that is further coupled to the motor, wherein the evaporator bus and the condenser bus comprise an AC-DC converter coupled to at least one DC-DC buck converter, wherein the at least one DC-DC buck converter is used to convert voltage from the distribution bus for the at least one evaporator and the at least one condenser.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises an AC-DC converter coupled to a DC-AC converter that is further coupled to the motor, wherein the evaporator bus comprises an AC-DC converter coupled to a DC-DC buck converter that is further coupled to the at least one evaporator, wherein the condenser bus comprises an AC-DC converter coupled to a DC-DC buck converter that is further coupled to the at least one condenser.

In addition to one or more of the features described herein, or as an alternative, further embodiments include a compressor bus that comprises an AC-DC converter coupled to a DC-AC converter that is further coupled to the motor, wherein the evaporator bus comprises an AC-DC converter coupled to a DC-AC converter that is further to the at least one evaporator, wherein the condenser bus comprises an AC-DC converter coupled to a DC-AC converter that is further coupled to the at least one condenser.

The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, that the following description and drawings are intended to be illustrative and explanatory in nature and non-limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

FIG. 1 depicts an exemplary electrical architecture for a transport refrigeration unit (TRU) configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 2 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 3 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 4 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 5 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 6 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 7 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 8 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 9 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 10 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 11 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 12 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 13 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 14 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 15 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 16 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 17 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure;

FIG. 18 depicts an exemplary electrical architecture for a TRU configured to receive low-voltage power, in accordance with one or more embodiments of the disclosure; and

FIG. 19 depicts an exemplary tractor trailer system having a transport refrigeration unit and a cargo compartment in an exemplary embodiment.

DETAILED DESCRIPTION

FIG. 1 depicts an electrical architecture for a system 100 using a low-voltage power source in accordance with one or more embodiments of the disclosure. As shown in FIG. 1 , the system 100 utilizes a direct current (DC) source as a source of power. In one or more embodiments of the disclosure, low-voltage can define a range of voltage between 1-100V. In a non-limiting example, the DC source is a low voltage battery source, i.e., 48 VDC battery. The DC source is coupled to the distribution network which can include a distribution bus 104. As shown in FIG. 1 , for example, the distribution bus 104 is a low-voltage DC distribution bus, i.e., 48 VDC bus, that can be coupled to one or more loads such as a motor 106 and a DC/DC buck converter. The motor 106 may be mechanically coupled to a compressor 120, i.e., open drive compressor. The mechanical coupling of the motor 106 to the compressor 120 may comprise any known mechanical coupling.

The distribution bus 104 may be coupled to a compressor bus 122, an evaporator bus 124, and a condenser bus 126. In different embodiments, the distribution bus may be further coupled to an auxiliary unit bus 130. The evaporator bus 124 and condenser bus 126 may be coupled to a single DC/DC buck converter to reduce the voltage to operate the evaporator fans 112 and condenser fans 114. The DC/DC buck converter is configured to reduce or step-down the voltage provided by the distribution bus 104 to low-voltage, i.e., 12 VDC bus.

FIG. 2 depicts an electrical architecture for a system 200 using a low-voltage power source in accordance with one or more embodiments of the disclosure. As shown in FIG. 2 , the system 200 includes the DC source 102 and similar loads (evaporator fan 112, condenser fan 114, auxiliary unit 116, compressor 120) as shown in FIG. 1 . The distribution network of FIG. 2 can include a distribution bus 210. The distribution bus 210 may be a low-voltage DC distribution bus that is coupled to the DC source 102, and the distribution bus 210 may also provide the same voltage as the DC source 102. The distribution bus 210 may be coupled to a compressor bus 222, an evaporator bus 224, and a condenser bus 226. The evaporator bus 224 and condenser bus 226can include respective DC/DC buck converters to reduce the voltage to operate the evaporator fan 112 and condenser fan 114, respectively as shown in FIG. 2 . In different embodiments, the distribution bus may be further coupled to an auxiliary unit bus 130.

FIG. 3 depicts an electrical architecture for a system 200 using a low-voltage power source in accordance with one or more embodiments of the disclosure. As shown in FIG. 3 , the system 300 includes the DC source 102 and similar loads (evaporator fan 112, condenser fan 114, auxiliary unit 116, compressor 120) as shown in FIG. 1 . The distribution network of FIG. 3 can include a distribution bus 310. The distribution bus 310 may be a low-voltage DC distribution bus that is coupled to the DC source 102, and the distribution bus 310 may also provide the same voltage as the DC source 102. The distribution bus 310 may be coupled to a compressor bus 322, an evaporator bus 324, and a condenser bus 326. In different embodiments, the distribution bus may be further coupled to an auxiliary unit bus 130.

The compressor bus 322 can include a motor 106, where the motor 106 is operably coupled to the compressor 120. The evaporator bus 324 can include a DC/DC boost converter that is coupled to a DC/AC converter. In this non-limiting example, the DC/DC boost converter is configured to increase or step-up the 48 VDC to 750 VDC, and the DC/AC converter is configured to convert the 750 VDC to 460 VAC that is provided for the operation of the evaporator fan 112.

The condenser bus 326 can include a DC/DC boost converter that is coupled to the DC/AC converter. Similar to the evaporator bus, the DC-DC boost converter is configured to increase or step-up the 48 VDC to 750 VDC, and the DC/AC converter is configured to convert the 750 VDC to 460 VAC that is provided for the operation of the condenser fan 114. The auxiliary unit bus 130 may include a DC/DC buck converter to step-down the voltage of the distribution bus 210 to an appropriate voltage for any connected auxiliary units 116.

FIG. 4 depicts an electrical architecture of a system 400 for a low-voltage power source in accordance with one or more embodiments of the disclosure. As shown in FIG. 4 , the system 400 includes the DC source 102 and similar loads (evaporator fan 112, condenser fan 114, auxiliary load 116, compressor 120) as shown in FIG. 1 . The distribution network of FIG. 4 may include a distribution bus 410 that is coupled to the compressor bus 422, the evaporator bus 424, and the condenser bus 426. In different embodiments, the distribution bus 410 may further be coupled to an auxiliary unit bus 130. The compressor bus 422 can include a DC/DC boost converter that is coupled to the distribution bus 410, and the DC/DC boost converter is further coupled to a DC/AC converter to operate the motor 120. In a non-limiting example, the DC/DC boost converter converts 48 VDC from the distribution bus 410 to 750 VDC, and the DC/AC converter converts the 750 VDC to 460 VAC. In FIG. 4 , the evaporator bus 424 and the condenser bus 426 are coupled to a single DC/DC buck converter to convert the voltage from the distribution bus 410 for the evaporator fans 112 and the condenser fans 114.

FIG. 5 depicts an electrical architecture of a system 500 for a low-voltage power source in accordance with one or more embodiments of the disclosure. As shown in FIG. 5 , the system 500 includes the DC source 102 and similar loads (evaporator fan 112, condenser fan 114, auxiliary load 116, compressor 120) as shown in FIG. 1 . The distribution network of FIG. 5 may include a distribution bus 510 that is coupled to the compressor bus 522, the evaporator bus 524, and the condenser bus 526.

In different embodiments, the distribution bus 510 may further be coupled to an auxiliary unit bus 130.

The compressor bus 522 can include a DC/DC boost converter that is coupled to a DC/AC converter. In this non-limiting example, the DC/DC boost converter is configured to increase or step-up the 48 VDC to 750 VDC, and the DC/AC converter is configured to convert the 750 VDC to 460 VAC that is provided for the operation of the compressor 120.

The evaporator bus 524 can comprise a DC/DC buck converter that is configured to step-down the voltage of the distribution bus 510 from 48 VDC to 12 VDC for the operation of the evaporator fan 112. Similarly, the condenser bus 526 can include a DC/DC buck converter that is configured step-down the voltage of the distribution bus 510 from 48 VDC to 12 VDC for the operation of the condenser fan 114.

FIG. 6 depicts an electrical architecture for a system 600 using a low-voltage power source in accordance with one or more embodiments of the disclosure. As shown in FIG. 6 , the system 600 includes the DC source 102 and similar loads (evaporator fan 112, condenser fan 114, auxiliary load 116, compressor 120) as shown in FIG. 1 . The distribution network of FIG. 6 may be a distribution bus 610 that is coupled to the compressor bus 622, the evaporate bus 624, and the condenser bus 626. In different embodiments, the distribution bus 610 may further be coupled to an auxiliary unit bus 130.

In one or more embodiments of the disclosure, the compressor bus 622 can include a DC/DC boost converter that is coupled to the DC/AC converter. In this non-limiting example, the DC-DC boost converter is configured to increase the 48 VDC to 750 VDC and the DC/AC converter is configured to convert the 750 VDC to 460 VAC that is provided for the operation of the compressor 120.

Similarly, the evaporator bus 624 and the condenser bus 626 each include a DC-DC boost converter that is coupled to a DC/AC converter. In this non-limiting example, each DC-DC boost converter is configured to increase or step-up the 48 VDC to 750 VDC and each DC/AC converter is configured to convert the 750 VDC to 460 VAC to operate the evaporator fan 112 and the condenser fan 114, respectively.

FIG. 7 depicts an electrical architecture of a system 700 for a low-voltage power source in accordance with one or more embodiments of the disclosure. As shown in FIG. 7 , the system 700 includes the DC source 102 and similar loads (evaporator fan 112, condenser fan 114, auxiliary load 116, compressor 120) as shown in FIG. 1 . The distribution network of FIG. 7 may include a distribution bus 710 that is coupled to the compressor bus 722, the evaporator bus 724, and the condenser bus 726. In different embodiments, the distribution bus 710 may further be coupled to an auxiliary unit bus 130. The compressor bus 722 can include a DC/DC buck converter that is coupled to the distribution bus 410, and the DC/DC buck is further coupled to a DC motor. In a non-limiting example, the DC/DC buck converter converts 750 VDC from the distribution bus 710 to 48 VDC to operate the DC motor. In FIG. 7 , the evaporator bus 724 and the condenser bus 726 are coupled to a single DC/DC buck converter to convert the voltage from the distribution bus 710 for the evaporator fans 112 and the condenser fans 114.

FIG. 8 depicts an electrical architecture for a system 800 using a low-voltage power source in accordance with one or more embodiments of the disclosure. The distribution network of FIG. 8 can include a DC/DC boost converter that is coupled to the DC source 102. The DC/DC boost converter can step-up the voltage of the DC source 102 for a distribution bus 810. The distribution bus 810 may be a high-voltage DC distribution bus, and may be coupled to the compressor bus 822, the evaporator bus 824, and the condenser bus 826. In different embodiments, the distribution bus 810 may further be coupled to an auxiliary unit bus 130.

The compressor bus 822 can include a DC/DC buck converter coupled to a motor used to drive a compressor. The DC/DC buck converter can be configured to step-down the voltage of the high-voltage DC distribution bus. The evaporator bus 824 may comprise DC/DC buck converter to step-down the voltage of the high-voltage DC distribution bus to a lower DC voltage for operation of the evaporator fan 112. Similarly, the condenser bus 826 may comprise DC/DC buck converter to step-down the voltage of the high-voltage DC distribution bus to a lower DC voltage for operation of the condenser fan 114.

FIG. 9 depicts an electrical architecture for a system 900 using a low-voltage power source in accordance with one or more embodiments of the disclosure. The distribution network of FIG. 9 can include a DC/DC boost converter that is coupled to the DC source 102. The distribution bus 910 may be a high-voltage DC distribution bus, and may be coupled to the compressor bus 922, the evaporator bus 924, and the condenser bus 926. In different embodiments, the distribution bus 910 may further be coupled to an auxiliary unit bus 130.

The compressor bus 922 may comprise a DC/DC buck converter coupled to a motor used to drive a compressor. The DC/DC buck converter can be configured to step-down the voltage of the high-voltage DC distribution bus. The evaporator bus 924 may comprise a DC/AC converter to convert the power of the high-voltage DC distribution bus. For example, the DC/AC converter can be configured to convert the 750 VDC to 460 VAC to operate the evaporator fan 112. Similarly, the condenser bus 926 may comprise a DC/AC converter to convert the power of the high-voltage DC distribution bus. For example, the DC/AC converter can be configured to convert the 750 VDC to 460 VAC to operate the condenser fan 114.

FIG. 10 depicts an electrical architecture of a system 1000 for a low-voltage power source in accordance with one or more embodiments of the disclosure. As shown in FIG. 10 , the system 1000 includes the DC source 102 and similar loads (evaporator fan 112, condenser fan 114, auxiliary load 116, compressor 120) as shown in FIG. 1 . The distribution network of FIG. 10 may include a distribution bus 1010 that is coupled to the compressor bus 1022, the evaporator bus 1024, and the condenser bus 1026. In different embodiments, the distribution bus 1010 may further be coupled to an auxiliary unit bus 130. The compressor bus 1022 can include a DC/AC converter to operate the motor 120. In a non-limiting example, the DC/AC converter converts the 750 VDC from the distribution bus 1010 to 460 VAC to operate the motor 120. In FIG. 10 , the evaporator bus 1024 and the condenser bus 1026 are coupled to a single DC/DC buck converter to convert the voltage from the distribution bus 1010 for the evaporator fans 112 and the condenser fans 114.

FIG. 11 depicts an electrical architecture for a system 1100 using a low-voltage power source in accordance with one or more embodiments of the disclosure. The distribution network of FIG. 11 can include a DC/DC boost converter that is coupled to the DC source 102. The distribution bus 1110 may be a high-voltage DC distribution bus, and may be coupled to the compressor bus 1122, the evaporator bus 1124, and the condenser bus 1126. In different embodiments, the distribution bus 1110 may further be coupled to an auxiliary unit bus 130.

The compressor bus 1122 may comprise a DC/AC converter for the operation of the compressor 120. The DC/AC converter is configured to convert the power of the distribution bus 1110. For example, the DC/AC converter can be configured to convert the 750 VDC to 460 VAC to operate the compressor 120.

The evaporator bus 1124 may comprise DC/DC buck converter to step-down the voltage of the high-voltage DC distribution bus to a lower DC voltage for operation of the evaporator fan 112. Similarly, the condenser bus 1126 may comprise DC/DC buck converter to step-down the voltage of the high-voltage DC distribution bus to a lower DC voltage for operation of the condenser fan 114.

FIG. 12 depicts an electrical architecture for a system 1200 for a low-voltage power source in accordance with one or more embodiments of the disclosure. The distribution network of FIG. 12 can include a DC/DC boost converter that is coupled to the DC source 102. The distribution bus 1210 may be a high-voltage DC distribution bus, and may be coupled to the compressor bus 1222, the evaporator bus 1224, and the condenser bus 1226. In different embodiments, the distribution bus 1210 may further be coupled to an auxiliary unit bus 130.

The compressor bus 1222 can include a DC/AC converter for the operation of the compressor 120. The DC/AC converter is configured to convert the power of the distribution bus 1210. For example, the DC/AC converter can be configured to convert the 750 VDC to 460 VAC to operate the compressor 120.

The evaporator bus 1224 may comprise a DC/AC converter to convert the power of the high-voltage DC distribution bus. For example, the DC/AC converter can be configured to convert the 750 VDC to 460 VAC to operate the evaporator fan 112. Similarly, the condenser bus 1226 may comprise a DC/AC converter to convert the power of the high-voltage DC distribution bus. For example, the DC/AC converter can be configured to convert the 750 VDC to 460 VAC to operate the condenser fan 114.

FIG. 13 depicts an electrical architecture of a system 1300 for a low-voltage power source in accordance with one or more embodiments of the disclosure. As shown in FIG. 13 , the system 1300 includes the DC source 102 and similar loads (evaporator fan 112, condenser fan 114, auxiliary load 116, compressor 120) as shown in FIG. 1 . The distribution network of FIG. 13 can include a converter that is coupled to the DC power source 102 and a distribution bus 1310. The converter may comprise a DC/DC/AC converter that is operable to convert the power from the DC power source 102 to high-voltage AC for distribution to various loads over a distribution bus 1310.The distribution network of FIG. 13 may include a distribution bus 1310 that is coupled to the compressor bus 1322, the evaporator bus 1324, and the condenser bus 1326. In different embodiments, the distribution bus 1310 may further be coupled to an auxiliary unit bus 130. The compressor bus may comprise an AC/DC converter that is coupled to a DC/DC buck converter that is further coupled to a motor. The AC/DC converter may be configured to convert the high-voltage AC from the distribution 1310 to DC voltage and the DC/DC buck converter may be operable to step-down the DC voltage, i.e., 48 VDC, to a voltage that is appropriate to operate the motor of the compressor.

In FIG. 13 , the evaporator bus 1324 and the condenser bus 1326 are coupled to a single DC/DC buck converter that is further coupled to an AC/DC converter to convert the voltage from the distribution bus 1310 for the at least one evaporator fan 112 and the at least one condenser fan 114. In a non-limiting example, the AC/DC converter converts the 480 VAC to a DC voltage and the DC/DC buck converter converts the DC voltage to 12 VDC.

FIG. 14 depicts an electrical architecture for a system 1400 using a low-voltage power source in accordance with one or more embodiments of the disclosure. The distribution network of FIG. 14 can include a converter that is coupled to the DC power source 102 and a distribution bus 1410. The converter may comprise a DC/DC/AC converter that is operable to convert the power from the DC power source 102 to high-voltage AC for distribution to various loads over a distribution bus 1410. The various loads may include such loads as the evaporator fan 112, the condenser fan 114, the auxiliary unit 116, and the compressor 120 shown in FIG. 1 .

The distribution bus 1410 may be a high-voltage AC distribution bus, i.e., 480 VAC. The distribution bus 1410 may be coupled to a compressor bus 1422, an evaporator bus 1424, and a condenser bus 1426. In a further embodiment, the distribution bus 1410 may be coupled to an auxiliary unit bus 130 including, for example, a battery charger that is operable to charge a connected battery.

The compressor bus 1422 may comprise an AC/DC converter that is coupled to a DC/DC buck converter that is further coupled to a motor. The AC/DC converter may be configured to convert the high-voltage AC from the distribution 1410 to DC voltage and the DC/DC buck converter may be operable to step-down the DC voltage, i.e., 48 VDC, to a voltage that is appropriate to operate the motor of the compressor.

The evaporator bus 1424 and the condenser bus 1426 may each comprise an AC/DC converter that is coupled to a DC/DC buck converter to condition the power to operate the evaporator fan 112 and the condenser fan 114, respectively.

FIG. 15 depicts an electrical architecture for a system 1500 using a low-voltage power source in accordance with one or more embodiments of the disclosure. The distribution network of FIG. 15 can include a converter that is coupled to the DC power source 102 and distribution bus 1510. The converter may comprise a DC/DC/AC converter that is operable to convert the power from the DC power source 102 to high-voltage AC for distribution to various loads over a distribution bus 1510. The first stage of the DC/DC/AC converter can step-up the voltage of the DC source 102 to the appropriate level and then convert the DC to AC for the distribution bus 1510. The various loads may include such loads as the evaporator fan 112, the condenser fan 114, the auxiliary unit 116, and the compressor 120 shown in FIG. 1 .

The distribution bus 1510 may be a high-voltage AC distribution bus, i.e., 480 VAC, and may be coupled to a compressor bus 1522, an evaporator bus 1524, and a condenser bus 1526. In a further embodiment, the distribution bus 1510 may be coupled to an auxiliary unit bus 130 including, for example, a battery charger that is operable to charge a connected battery.

The compressor bus 1522 may comprise an AC/DC converter that is coupled to a DC/DC buck converter that is further coupled to a motor. The AC/DC converter may be configured to convert the high-voltage AC from the distribution 1510 to DC voltage and the DC/DC buck converter may be operable to step-down the DC voltage, i.e., 48 VDC, to a voltage that is appropriate to operate the motor of the compressor.

The evaporator bus 1524 may comprise an AC/DC converter that is coupled to the high-voltage DC distribution bus and the AC/DC converter is further coupled to the DC/AC converter. For example, the AC/DC converter can be configured to convert the 480 VAC to 750 VCD, and the DC/AC converter can be configured to convert the 750 VDC to 460 VAC to operate the at least one evaporator fan 112. Similarly, the condenser bus 1526 may comprise AC/DC converter that is coupled to the high-voltage DC distribution bus and the AC/DC converter is further coupled to the DC/AC converter to operate the at least one condenser fan 114.

FIG. 16 depicts an electrical architecture of a system 1600 for a low-voltage power source in accordance with one or more embodiments of the disclosure. As shown in FIG. 16 , the system 1600 includes the DC source 102 and similar loads (evaporator fan 112, condenser fan 114, auxiliary load 116, compressor 120) as shown in FIG. 1 . The distribution network of FIG. 16 may include a distribution bus 1610 that is coupled to the compressor bus 1622, the evaporator bus 1624, and the condenser bus 1626. In different embodiments, the distribution bus 1610 may further be coupled to an auxiliary unit bus 130. The compressor bus 1622 can include an AC/DC converter that is coupled to the high-voltage AC distribution bus and the AC/DC converter is further coupled to the DC/AC converter. In the non-limiting example, the AC/DC converter can be configured to convert the 480 VAC to 750 VCD, and the DC/AC converter can be configured to convert the 750 VDC to 460 VAC to operate the motor 120. In FIG. 16 , the evaporator bus 1624 and the condenser bus 1626 are coupled to a single DC/DC buck converter to convert the voltage from the distribution bus 1610 for the evaporator fans 112 and the condenser fans 114.

FIG. 17 depicts an electrical architecture for a system 1700 using low-voltage power source in accordance with one or more embodiments of the disclosure. The distribution network of FIG. 17 can include a converter that is coupled to the DC power source 102 and a distribution bus 1710. The converter may comprise a DC/DC/AC converter that is operable to convert the power from the DC power source 102 to high-voltage AC for distribution to various loads over a distribution bus 1710. The various loads may include such loads as the evaporator fan 112, the condenser fan 114, the auxiliary unit 116, and the compressor 120 shown in FIG. 1 .

The distribution bus 1710 may be a high-voltage AC distribution bus. The distribution bus 1710 of FIG. 17 may be coupled to a compressor bus 1722, an evaporator bus 1724, and a condenser bus 1726. The compressor bus 1722 can include an AC/DC converter that is coupled to a DC/AC converter. The AC/DC converter may convert the 480 VAC from the distribution bus to 750 VDC and the DC/AC converter may convert the 750 VDC to 460 VAC to provide power to operate the compressor 120.

The evaporator bus 1724 and the condenser bus 1726 may each comprise an AC/DC converter that is coupled to a DC/DC buck converter to condition the power to operate the evaporator fan 112 and the condenser fan 114, respectively.

FIG. 18 depicts an electrical architecture for a system 1800 having a low-voltage power source in accordance with one or more embodiments of the disclosure. The distribution network of FIG. 18 can include a converter that is coupled to the DC power source 102 and a distribution bus 1810. The converter may comprise a DC/DC/AC converter that is operable to convert the power from the DC power source 102 to high-voltage AC for distribution to various loads over a distribution bus 1810. The various loads may include such loads as the evaporator fan 112, the condenser fan 114, the auxiliary unit 116, and the compressor 120 shown in FIG. 1 .

The distribution bus 1810 may be a high-voltage AC distribution bus, and may be coupled to a compressor bus 1822, an evaporator bus 1824, and a condenser bus 1826. The compressor bus 1822 can include an AC/DC converter that is coupled to a DC/AC converter. The AC/DC converter may convert the 480 VAC from the distribution bus to 750 VDC and the DC/AC converter may convert the 750 VDC to 460 VAC to provide power to operate the compressor 120. Similarly, the evaporator bus 1824 and the condenser bus 1826 each comprise an AC/DC converter to convert the AC voltage from the distribution bus to a DC voltage and a DC/AC converter to convert the DC voltage from the AC/DC converter to operate the connected refrigeration equipment.

Shown in FIG. 19 is an embodiment of a tractor trailer system 1900. The tractor trailer system 1900 includes a tractor 1902 including an operator's compartment or cab 1904 and also including an engine, which acts as the drive system of the tractor trailer system 1900. A trailer 1906 is coupled to the tractor 1902. The trailer 1906 is a refrigerated trailer 1906 and includes a top wall 1908, a directly opposed bottom wall 1910, opposed side walls 1912, and a front wall 1914, with the front wall 1914 being closest to the tractor 1902. The trailer 1906 further includes a door or doors (not shown) at a rear wall 1916, opposite the front wall 1914. The walls of the trailer 1906 define a cargo compartment. The trailer 1906 is configured to maintain a cargo 1918 located inside the cargo compartment at a selected temperature through the use of a transport refrigeration unit 1920 located on the trailer 1906. The transport refrigeration unit 1920, as shown in FIG. 19 , is located at or attached to the front wall 1914.

A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof.

While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims. 

What is claimed is:
 1. A low-voltage system of a transport refrigeration unit (TRU), the system comprising: a low-voltage direct current (LVDC) source; and a distribution bus coupled to the LVDC, wherein the distribution bus is coupled to a compressor, at least one condenser fan, and at least one evaporator fan.
 2. The low-voltage system of claim 1, wherein the distribution bus is a low voltage DC distribution bus.
 3. The low-voltage system of claim 2, wherein the distribution bus is coupled to a compressor bus, an evaporator bus, and a condenser bus.
 4. The low-voltage system of claim 3, wherein the compressor bus comprises a DC motor that is mechanically coupled to an open drive compressor, wherein the evaporator bus and the condenser bus are coupled to at least one DC-DC buck converter that is used to convert voltage from the distribution bus for the at least one evaporator fan and the at least one condenser fan.
 5. The low-voltage system of claim 3, wherein the compressor bus comprises a DC motor that is mechanically coupled to an open drive compressor, wherein the evaporator bus comprises at least one first DC-DC buck converter to convert voltage from the distribution bus for the at least one evaporator fan, wherein the condenser bus comprises at least one second DC-DC buck converter to convert voltage from the distribution bus for the at least one condenser fan, wherein the at least one first DC-DC buck converter and the at least one second DC-DC converter are different DC-DC converters.
 6. The low-voltage system of claim 3, wherein the compressor bus comprises a DC motor that is mechanically coupled to an open drive compressor, wherein the evaporator bus comprises a DC-DC boost converter coupled to the at least one DC-AC converter, wherein the condenser bus comprises a DC/DC boost converter coupled to the at least one DC-AC converter.
 7. The low-voltage system of claim 3, wherein the compressor bus comprises a DC/DC boost converter coupled to a DC/AC converter, wherein the evaporator bus and the condenser bus are coupled to at least one DC-DC buck converter that is used to convert voltage from the distribution bus for the at least one evaporator fan and the at least one condenser fan.
 8. The low-voltage system of claim 3, wherein the compressor bus comprises a DC-DC boost converter coupled to a DC/AC converter, wherein the evaporator bus comprises at least one first DC-DC buck converter coupled to the at least one evaporator fan, wherein the condenser bus comprises at least one second DC-DC buck converter coupled to the at least one condenser fan, wherein the at least one first DC-DC buck converter and the at least one second DC-DC converter are different DC-DC converters.
 9. The low-voltage system of claim 3, wherein the compressor bus comprises a DC-DC boost converter that is coupled to a DC-AC converter, wherein the evaporator bus comprises a DC-DC boost converter that is coupled to a DC-AC converter that is further coupled to the at least one evaporator fan, wherein the condenser bus comprises a DC-DC boost converter that is coupled to a DC-AC converter that is further coupled to the at least one condenser fan.
 10. The low-voltage system of claim 1, further comprising a first converter coupling the LVDC source to the distribution bus, wherein the distribution bus is a high-voltage DC distribution bus that is further coupled to a compressor bus coupled to the compressor, an evaporator bus coupled to the at least one evaporator fan, and a condenser bus coupled to the at least one condenser fan, wherein the first converter is a DC-DC boost converter configured to increase a voltage from the LVDC source.
 11. The low-voltage system of claim 10, wherein the compressor bus comprises a DC motor and a DC-DC buck converter configured to convert voltage from the distribution bus, wherein the DC motor is mechanically coupled to an open drive compressor, wherein the evaporator bus and the condenser bus are coupled to at least one DC-DC buck converter that is used to convert voltage from the distribution bus for the at least one evaporator fan and the at least one condenser fan.
 12. The low-voltage system of claim 10, wherein the compressor bus comprises a DC motor and a DC-DC buck converter configured to convert voltage from the distribution bus, wherein the DC motor is mechanically coupled to an open drive compressor, wherein the evaporator bus comprises at least one first DC-DC buck converter coupled to the at least one evaporator, wherein the condenser bus comprises at least one second DC-DC buck converter coupled to the at least one condenser fan, wherein the at least one first DC-DC buck converter and the at least one second DC-DC converter are different DC-DC converters.
 13. The low-voltage system of claim 10, wherein the compressor bus comprises a DC motor and a DC-DC buck converter to convert voltage from the distribution bus, wherein the DC motor is mechanically coupled to an open drive compressor, wherein the evaporator bus comprises at least one DC-AC converter coupled to the at least one evaporator, wherein the condenser bus comprises at least one DC-AC converter coupled to the at least one condenser fan.
 14. The low-voltage system of claim 10, wherein the compressor bus comprises a DC-AC converter coupled to a motor, wherein the evaporator bus and the condenser bus are coupled to at least one DC-DC buck converter that is used to convert voltage from the distribution bus for the at least one evaporator fan and the at least one condenser fan.
 15. The low-voltage system of claim 10, wherein the compressor bus comprises a DC-AC converter coupled to a motor, wherein the evaporator bus comprises at least one first DC-DC buck converter coupled to the at least one evaporator, wherein the condenser bus comprises at least one second DC-DC buck converter coupled to the at least one condenser fan, wherein the at least one first DC-DC buck converter and the at least one second DC-DC buck converter are different DC-DC buck converters.
 16. The low-voltage system of claim 10, wherein the compressor bus comprises a DC-AC converter coupled to a motor, wherein the evaporator bus comprises at least one first DC-AC converter coupled to the at least one evaporator, wherein the condenser bus comprises at least one second DC-AC converter coupled to the at least one condenser fan, wherein the at least one first DC-AC converter and the at least one second DC-AC converter are different DC-AC converters.
 17. The low-voltage system of claim 1, further comprising a first converter coupling the LVDC source to the distribution bus, wherein the distribution bus is a high-voltage AC distribution bus, wherein the distribution bus is coupled to the compressor bus, the evaporator bus, and the condenser bus.
 18. The low-voltage system of claim 17, wherein the compressor bus comprises an AC-DC converter coupled to a DC-DC buck converter that is further coupled to the DC motor, wherein the DC motor is further mechanically coupled to an open drive compressor, wherein the evaporator bus and the condenser bus comprise an AC-DC converter coupled to at least one DC-DC buck converter, wherein the at least one DC-DC buck converter that is used to convert voltage from the distribution bus for the at least one evaporator fan and the at least one condenser fan.
 19. The low-voltage system of claim 17, wherein the compressor bus comprises an AC-DC converter coupled to a DC-DC buck converter that is further coupled to the DC motor, wherein the DC motor is further mechanically coupled to an open drive compressor, wherein the evaporator bus comprises an AC-DC converter coupled to a DC-DC buck converter that is further coupled to the at least one evaporator, wherein the condenser bus comprises an AC-DC converter coupled to a DC-DC buck converter that is further coupled to the at least one condenser fan.
 20. The low-voltage system of claim 17, wherein the compressor bus comprises an AC-DC converter coupled to a DC-DC buck converter coupled to the DC motor, wherein the DC motor is further mechanically coupled to an open drive compressor, wherein the evaporator bus comprises an AC-DC converter coupled to a DC-AC converter, wherein the condenser bus comprises an AC-DC converter coupled to an DC-AC converter.
 21. The low-voltage system of claim 17, wherein the compressor bus comprises an AC-DC converter coupled to a DC-AC converter that is further coupled to the motor, wherein the evaporator bus and the condenser bus comprise an AC-DC converter coupled to at least one DC-DC buck converter, wherein the at least one DC-DC buck converter is used to convert voltage from the distribution bus for the at least one evaporator fan and the at least one condenser fan.
 22. The low-voltage system of claim 17, wherein the compressor bus comprises an AC-DC converter coupled to a DC-AC converter that is further coupled to the motor, wherein the evaporator bus comprises an AC-DC converter coupled to a DC-DC buck converter that is further coupled to the at least one evaporator fan, wherein the condenser bus comprises an AC-DC converter coupled to a DC-DC buck converter that is further coupled to the at least one condenser fan.
 23. The low-voltage system of claim 17, wherein the compressor bus comprises an AC-DC converter coupled to a DC-AC converter that is further coupled to the motor, wherein the evaporator bus comprises an AC-DC converter coupled to a DC-AC converter that is further to the at least one evaporator fan, wherein the condenser bus comprises an AC-DC converter coupled to a DC-AC converter that is further coupled to the at least one condenser fan. 